For example, an object detection device such as a laser radar for vehicle mounting projects light from light emitting elements, and detects whether there is a target based on a result of reflected light of the projected light that is received by light receiving elements. In addition, there is also an object detection device that projects light from light emitting elements and detects a distance from the object detection device to a target, based on the time taken for light receiving elements to receive reflected light from the target.
For the light emitting elements, laser diodes, etc., are used. For the light receiving elements, photodiodes, etc., are used. For example, as described in JP 2003-149338 A, JP 2014-59222 A, JP 2014-52366 A, JP 2014-32149 A, JP 2014-235075 A, JP 2015-137951 A, WO 2016/012579 A, and DE 102014110510 A, light projected from light emitting elements passes through optical components of a light projection system such as a light projecting lens and a mirror, and is deflected by an optical deflector, and a target is irradiated with the deflected light. Then, light reflected off the target is deflected by the optical deflector, and then the deflected light passes through optical components of a light reception system such as a mirror and a light receiving lens, and is received by light receiving elements. Note that, in JP 2003-149338 A, reflected light from a target is collected by a light receiving lens without passing through an optical deflector, and is received by light receiving elements. The optical deflector is composed of, for example, a rotating mirror.
To project and receive light to/from a target, in JP 2003-149338 A, JP 2014-59222 A, JP 2014-32149 A, and DE 102014110510 A, light emitting elements and light receiving elements are mounted on different substrates. In JP 2014-235075 A, light emitting elements and light receiving elements are mounted on the same plate-like member (reference sign 1a). In all of JP 2003-149338 A, JP 2014-59222 A, JP 2014-32149 A, DE 102014110510 A, and JP 2014-235075 A, the light emitting elements are mounted on a mounting surface of the substrate so as to project light mainly in a direction perpendicular to the mounting surface. The light receiving elements are mounted on a mounting surface of the substrate so as to receive light coming mainly in a direction perpendicular to the mounting surface.
In addition, in JP 2003-149338 A, the substrate having mounted thereon the light emitting elements and the substrate having mounted thereon the light receiving elements are disposed in parallel to each other on the same plane. In JP 2014-59222 A and DE 102014110510 A, the substrate having mounted thereon the light emitting elements and the substrate having mounted thereon the light receiving elements are disposed perpendicularly to each other.
When the light emitting elements and the light receiving elements are mounted on different substrates, if one substrate and the other substrate are disposed side by side such that their substrate surfaces are located on the same plane, then the object detection device increases in size in a side-by-side disposition direction. Meanwhile, positioning two substrates such that their substrate surfaces are perpendicular to each other is more difficult than positioning two substrates such that their substrate surfaces are parallel to each other.